Apparatus for feeding pulverized fuel



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APPARATUS FOR FEEDING PULVERIZED FUEL Filed Jan. 26 1925 3 Sheets-Sheet l July 1 1924 11,499,396

H. MUELLER APPARATUS FOR FEEDING PULVERIZED FUEL Filed Jan. 26. 1923 3 Sheets-Sheet 2 3 fyfl,

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APPARATUS FOR FEEDING PULVERIZED FUEL Filed Jan. 26. 1925 s Sheets-Sheet 3 INVENTOR v wvw 7 41;, wiz

Patented July 1, 1924.

' UNITED STATES PATENT. OFFICE.

HENRY MUELLER. 0F PITTSBURGH, PENNSYLVANIA. ASSIGNOR TO UNITED EN- GINEERING AND FOUNDRY COMPANY, OF PITTSBURGH, PENNSYLVANIA, A COB- PORATION OF PENNSYLVANIA.

APPARATUS FOR FEEDING PULVERIVZED FUEL.

To all whom it may concern.

Be it known that I. HENRY MUELLER, a citizen of the United States. residing at Pittsburgh, county of Allegheny, and State of Pennsylvania. have inventeda new and useful lmprovementin Apparatus for Feeding ulverized Fuel. of which the following is a full, clear, and exact description.

The present invention relates broadly to the art of pulverized fuel feeding. and more particularly to a method and apparatus whereby certain disadvantageous features of the prior art constructions are overcome. i

It has heretofore been proposed to feed pulverized fuel by means of a single screwconveyor. The difficulty with such constructions has been the lack of uniformity of feed and the tendency of the fuel to continue to flow after the conveyor was stopped due to the fact that the single screw-conveyor offered a continuous pas sage for the finely divided fuel. This tendency of the fuel to feed unevenly and to continue to flow after the stoppage ofv the conveyor often produced whatis known in the art as flushing. To overcomethis disadvantage of the single scrmv-con-veyot'. it has been proposed to provide a pair of cooperating screws as shown in the patent to Covert. No. 1,197,799, of September 12. 1916. This type of feeder, however. has been found in actual practice to offer numerous disadvantages. such as rapid wearing of the parts, due to the constantgrinding action of one screw upon the other. and relatively large power consumption, due to the necessity for rotating the screws at a relatively high speed while overcoming a lar e amount of frictional resistance.

15v the present invention the above mentioned and other disadvantages of the prior art constructions are overcome, an 'important object of the invention being to provide a fuel feeding system having a single rotating feeding member provided with peripheral fuel receiving means adapted to continuously and uniformly receive and discharge fuel. together with an auxiliarv air blast in contact with the discharge side of the rotating feeding member adapted to clean the fuel receiving'means in the periphery of said member of fuel and fill the same with air for aerating the fuel' livery to said rotating member.

A further object of the invention is to provide a main air supply and an auxiliary air supply. the auxiliary air supply-conveying the fuel in suspension from the discharge side of the rotating feeding member and discharging into the main air supply in such manner that the latter acts as an ejector for the auxiliary air supply and the fuel carried in suspension therein.

Further objects and advantagesof the invention will be apparent as the description proceeds.

prior to de- Theinvention is illustrated in the accom- I panymg drawings, in wh1ch:-

Figure 1 is a view showing my improved fuel feeding apparatusin'elevation. a portion-of the furnace being shown in section.

Figure 2 is a vertical sectional view of the rotating feeding member and of the means for conveying the fuel to and from said member, and'also showing the driving connections for said member.

Figure 3 is a sectional view taken on the line III- 1H, of Figure 2 and looking towards the right.

' Figure t is a plan view of the rotatable feeding drum.

Figure 5 is a fragmentary sectional view showing the flexible connection between the auxiliary and main air conduits.

Figure'6 is adet'ail view of the flexible diaphragm forming part of the connection shown in Figure 5.

Referring to the drawings. 1 indicates a housing or casing having a hopper 2 connected with a fuel feeding chute 3. Journaled in suitable hearings in the casing 1 is a shaft 4 upon which is mounted a drum 5. The drum 5 is fixed to the shaft 4 by means of an integral projection-6 on the drum cooperating with a cut-away or faceted portion 7 of the shaft, so that the drum and shaft areafiixed to each other against either bearings and ends of the drum, the latter are each provided with a plurality of independent peripheral grooves 9. Each bearing 8 engages only a portion of the periphery of the corresponding end of the drum. the construction bein such that any of the pulverized fuel wluch finds its way into the grooves 9 at the upper side of the drum will simply be carried around ,in the rotation of thedrum and escape at the discharge side of the drum. In this manner the rinding.

pendent groove '10 will be gradually filled rom end to end with material from the hopper, and then, in the further rotation of the drum, will gradually empty its load at the discharge side of the drum, whereas, if the grooves were arranged parallel to the axis of the drum, each groove would be filled simultaneously from end to end with 'material from the hopper and would discharge its entire load at substantially the same instant. The present construction, therefore,

insures a su sta'ntially uniform feeding of the material from the hopper into the air line and obviates any dan er of flushing. Moreover, the provision of the independent diagonally arranged grooves revents flushing when the rotation o the drum is stripped. e I

wing to the relatively large peripheral area of the feeding drum with its series of independent grooves, the said drum can be rotated at a comparatively low speed, there-' b" enabling a small power consumption. 1 hr driving the drum, a small electric motor 11 is provided, which is attached to one end of the casing 1, as indicated in Figure 2, and drives the drum through the pinion 12, gear 13, pinion 14 and gear 15.

duit 16 communicates at its lower end with a hollow coupling member 17. A burner 18 is connected at one end to an end of the coupling member 17, and at its other end rojects into the opening 19 in a wall of the urnace 20. j

Branching oil from the main conduit 16 at the point 21 is an auxiliary air c'onduit22l This auxiliary air conduit 22 includes'asection 23 of the housing 1 arranged to carry the auxiliary air supply past and in contact with the discharge side of the rotatable drum 5 and in a direction parallel to the axis of the drum. The section 23 is provided with a cleaning opening closed by a screw plug 24. A suitable valve 25 is provided in the conduit 22 for regulating the auxiliary air supply.

The section 23 has formed at one end thereof an integral flange 2t3,'and clamped between this flange 2t) and a ring 27 by means of bolts 28 is an annular metal diaphragm 29. The peripheral edge portion of the diaphragm 29 is clamped between a flange 30 formed integral with one end of the coupling member 17 and a ring 31 secured to the flange 30 by bolts 32, a packing member 33 being interposed between the ring 31 and diaphragm 29. Threadedly connected at one end to the ring 27 and projecting into the coupling member 17 is a pipe 34 forming an extension of the conduit 22. The construction just described provides a flexible and adjustable connection between the main air conduit and the discharge end of the auxiliary air conduit, so as to take care of any slight inaccuracies of alinement between the fuel feedingapparatus and the furnace. When -it is desired to adjust the discharge end of the auxiliary conduit with respect to themain air conduit, this can be done by loosening the nuts on thebolts 32 so as to permit shifting of the diaphragm 29 in its own plane, after which the .nuts will be tightened again.

In the operation of the apparatus, the individual grooves in the rotating drum'are gradually filled with material from the, hopper and gradually discharge this material into the auxiliary air conduit at the discharge side of the drum. Since the auxiliary air supply sweeps past the drum in a direction substantial y parallel to the length of the grooves, the tendency of the auxiliary air supply is to clean the grooves of fuel and fill them with air, which is carried around in the grooves to aerate the fuel in the hopper. Since the discharge end of the auxiliary conduit 22 projects into the coupling member 17, the main air supply has an ejector action upon the auxiliary air supply and thefuel carried 1n suspenslon therein, thereby further insuring against flushing. e mainair supply conduit 18 represented by the reference numeral 16. The con- I' claim 1. In apparatus for feeding pulverized fuel, an auxiliary air conduit, means for feeding fuel into said conduit, a main air conduit, an extension detachably secured to said auxiliary conduit and projecting into the main conduit, 9. flexible annular diaphragm secured between flanges on the adacent ends of said auxiliary conduit and extension, and means adjustably clamping said diaphragm to said main conduit, substantially as described.

2. In apparatus for feeding pulverized fuel, an auxiliary air conduit, :1 source of fuel supply, a rotatable drum having a series mane of independent fuel receiving grooves in its periphery extending longitudinally thereof but in a direction diagonal to its axis for continuously and uniformly feeding material from said source of supply into said auxiliary conduit, and a main air conduit, the auxiliary air conduit being arranged to direct the air in contact with the discharge side of said drum in a direction longitudinally thereof and, throughout substantially the length thereof and having its discharge end projecting into said main airconduit, whereby the main air supply acts as an ejector for the auxiliary air supply and the material held in suspension therein, substantially as described.

3. In apparatus for feeding pulverized fuel, an auxiliary air conduit, means for feeding fuel into said auxiliary conduit, a main air conduit, the auxiliary conduit communicating at its discharge end with the main air conduit, and a flexible and adjustable connection between the main air conduit and the discharge end of the auxil- 'iary air conduit, substantially as described.

In testimony whereof I have hereunto set my hand.

HENRY MUELLER. 

